Syndrome of Inappropriate Antidiuretic Hormone (SIADH)/ Schwartz-Bartter syndrome-
Pathophysiology- As the name suggests this syndrome is caused by over secretion of Antidiuretic hormone (ADH) also known as vasopressin. When the body needs to retain more water ADH is secreted by the posterior pituitary gland. This will cause the kidneys to reabsorb water and put it back into systemic circulation. With SIADH ADH is release even when the body does not need to retain more water. This leads to fluid retention (increasing plasma volume) and hyponatremia. The increase in plasma volume increases glomerular filtration rate (GFR) and inhibit the release of renin and aldosterone. This increased sodium loss in urine further exacerbating the hyponatremia.
Signs/Symptoms-
Mild- Weakness, muscle cramps, loss of appetite, nausea and vomiting, and fatigue.
As fluid retention increase patient may present with
Increase weight gain,
Nervous system changes,
Personality changes,
Confusion,
Extreme muscle weakness.
Fluid overload-
Increased pulse quality,
Increased neck vein distention,
Crackles in lungs,
Increased peripheral edema (dependent edema is usually not present because only water is retained, not salt)
Reduced urine output.
May lead to pulmonary edema and heart failure (increased risk with patients with coexisting cardiac, kidney, pulmonary, or liver problems).
As hyponatremia increase as levels drop resulting in
Lethargy and headache
Decreased responsiveness
Seizures
Coma
Death
Labs/tests-
Serum sodium levels
Serum potassium
Serum osmolality
urine specific gravity and osmolality (2)
Causes-
Cancer is the leading causeSome cancers produce ADH and some cause the brain to secrete ADH.
Most common with carcinoma of the lung
Tumors in the brain are also a leading cause of SIADH.
Pancreatic, duodenal and GU carcinomas
Thymoma
Hodgkin’s and Non-Hodgkin’s lymphoma
Some cancers produce ADH and some cause the brain to secrete ADH.
Syndrome of inappropriate antidiuretic hormone secretion; SIADH
(3)
Cancer drug may also cause SIADH (e.g. morphine sulfate, cyclophosphamide).
Treatment-
Treat condition:
Maintain fluid restrictions (may be as low as 500-600ml/day)
Increase sodium intake
If tube feeing dilute feeding with saline (instead of plain water) and irrigate GI tubes with saline
If sodium becomes too low a hypertonic saline (3% NaCl) IV can be administered cautiously. Increased sodium may increase fluid overload and can cause heart failure.
Drug therapy (demeclocycline an antibiotic which works in opposition to ADH)
Treat cause:
Cancer therapy
Radiation
Chemotherapy
Interventions-
Prevent fluid overload
Fluid restriction
Promote excretion of water
Monitor for s/s of fluid overload every 2 hours
Monitor I&O’s and weight patient. A 2 or more pound increase with a day is a reason for concern (Remember 1kg = 1L).
Keep mucous membranes moist with swabs or mouth rinse
Assess for diminishing deep tendon reflexes
Check vital signs for possible
Tachycardia
Hypothermia
Increased B/P (2)
Monitor response to therapy
Teach patient and family about fluid restrictions and drug therapy
Injury prevention/provide safe environment.
Check LOC every 1-4hrs depending on patient’s condition.
Pathophysiology- As the name suggests this syndrome is caused by over secretion of Antidiuretic hormone (ADH) also known as vasopressin. When the body needs to retain more water ADH is secreted by the posterior pituitary gland. This will cause the kidneys to reabsorb water and put it back into systemic circulation. With SIADH ADH is release even when the body does not need to retain more water. This leads to fluid retention (increasing plasma volume) and hyponatremia. The increase in plasma volume increases glomerular filtration rate (GFR) and inhibit the release of renin and aldosterone. This increased sodium loss in urine further exacerbating the hyponatremia.
Signs/Symptoms-
Labs/tests-
- Serum sodium levels
- Serum potassium
- Serum osmolality
- urine specific gravity and osmolality (2)
Causes-- Cancer is the leading causeSome cancers produce ADH and some cause the brain to secrete ADH.
- Most common with carcinoma of the lung
- Tumors in the brain are also a leading cause of SIADH.
- Pancreatic, duodenal and GU carcinomas
- Thymoma
- Hodgkin’s and Non-Hodgkin’s lymphoma
Syndrome of inappropriate antidiuretic hormone secretion; SIADH
(3)
Treatment-Some cancers produce ADH and some cause the brain to secrete ADH.
Cancer drug may also cause SIADH (e.g. morphine sulfate, cyclophosphamide).
- Treat condition:
- Maintain fluid restrictions (may be as low as 500-600ml/day)
- Increase sodium intake
- If tube feeing dilute feeding with saline (instead of plain water) and irrigate GI tubes with saline
- If sodium becomes too low a hypertonic saline (3% NaCl) IV can be administered cautiously. Increased sodium may increase fluid overload and can cause heart failure.
- Drug therapy (demeclocycline an antibiotic which works in opposition to ADH)
- Treat cause:
- Cancer therapy
- Radiation
- Chemotherapy
Interventions-1.all content unless otherwise specified is from
Ignatavicius,, D. , & Workman, L. (2010). Medical-surgical nursing: patient-centered collaborative care. St. Louis Mo.: Saunders.
2. http://nursingcrib.com/critical-care-and-emergency-nursing/syndrome-of-inappropriate-antidiuretic-hormone-siadh/
3. http://www.virtualmedicalcentre.com/diseases.asp?did=149&title=syndrome-of-inappropriate-antidiuretic-hormone-secretion-siadh